A linear slide is defined as a base with varying lengths and a moving carriage to which a load is attached. The carriage tends to be a geometric shaped block with integrated linear bearings that can be either sliding elements or rolling balls.
A linear stage is defined as a linear slide that has a built-in drive mechanism. The most common drive mechanisms are lead screws, ball screws, timing belts, and any other method of linear movement.
Finally, there are powered linear stages which incorporate on the stage a method of moving the drive mechanism. The mode of powering the drive mechanism is usually provided by a rotary motor which could be a stepper, brushed, brushless, or servo motor.
Although, technically, there are tree different types, as described above, all types will be referred to herein as linear slides.
Linear slides that utilize rolling ball elements as bearing surfaces are a more expensive solution and are generally referred to as ball slides. A less expensive solution has a plain, sliding-element bearing between the carriage and the base. A primary design consideration with this type of linear slide is the bearing surface which wears over time and produces increased clearances between the carriage and the base of the slide. The wear in the carriage produces misalignment between the drive mechanism and the carriage, further increasing wear and reducing the efficiency of the slide.
There are manual adjustments integrated into some slides allowing the user to adjust the bearing surfaces in the carriage after significant wear occurs. However, these mechanisms require multiple parts and, without careful adjustment, the carriage can be shifted unevenly to one side of the base.
Accordingly, it is a principal object of the present invention to provide a linear slide with a self-compensating, or manually adjusted, plain bearing surface on the carriage.
It is a further object of the present invention to provide such a product which has an adjustment that uses minimal parts and forces the bearing surfaces to be equally adjusted to both sides of the base via one adjuster, providing an inexpensive bearing surface with the ability to have high positional accuracy and longer life expectancy than conventional products.
It is an additional object of the present invention to further exploit an inexpensive product approach by utilizing an extrusion for the base, as this is a cost effective manufacturing method that is easily configurable.
It is another object of the present invention to provide such a product that is tolerable to the uneven load conditions that are expected while also offering a multitude of mounting options.
A further object of the present invention is to provide an inexpensive method of attaching end plates to the extrusion, without secondary machining, to produce a complete linear stage.
An additional object of the present invention is to create an error-proof method of assembling the carriage.
Another object of the present invention is to provide such a carriage that has sliding surfaces with good finish and dimensional tolerances that do not increase the looseness of the carriage-to-base interface.
Other objects of the invention, as well as particular features and advantages thereof, will be apparent or be elucidated in the following description and the accompanying drawing figures.